Air distributing device



Sept. 16, 1941. F. J. KURTH AIR DISTRIBUTING DEVICE Filed March 20, 1939 Patented Sept. 16, 1941 AIR. DISTRIBUTING DEVICE Franz J.' Kurth, New York, N. Y., assignor to Anemostat Corporation of America, a corporation of Delaware Application March 20, 1939, Serial No. 262,971

6 Claims.

series of flaring passageways. In a device of this type some or all of the flaring members serve to deflect the supplied air laterally outward and to divide it into a plurality of separate streams which flow, respectively, forwardly through some or all of the separate passageways at reduced velocities as compared with the duct velocity of the air. Because the supplied air has a natural tendency to flow directly forwardly through a device of the type mentioned, and because it is deflected laterally outward by the flaring members, there is produced in the inner side portion of each passageway through which a forward flow of air takes place, a zone of high pressure as compared with the pressure in the outer side portion of each such passageway. As a consequence, instead of there being'a forward flow of air throughout the area of each such passageway, there occurs a rearward or aspirating flow of air in the outer side portion of each such passageway. Of course,

the rearwardly flowing or aspirated air merges with and is carried forwardly by the forwardly flowing air, with the result that there occurs, within the passageways and in advance I of the same, a more or less pronounced intermixing of the supplied air with the air of the room or other enclosure into which the supplied air is delivered. This is of decided advantage in eliminating sensation of draft in cases where there is a temperature differential between the supplied air .and the room or other enclosure air, as the supplied air is tempered by the room or enclosure air as it is delivered rather than after delivery. Thus, because of the mixing of the supplied air with the room or enclosure air, and because of the reduced velocity, diffused flow of air caused by the flaring memconstructed usually have comprised a minimum of five flaring members and four flaring passageways in order to obtain required diffusion and reducedvelocity of thesuppliedair. The number of flaring members included in a device of any given neck size is, of course, a measure of the cost of the device, the cost naturally varying with variation in the number of flaring members used. Therefore, it obviously is desirable to construct devices of the type mentioned with the fewest number of flaring members practicable commensurate with the obtaining of desired results respecting diffusion, mixing and reduced velocity of the air. When, however, attempts were made to reduce the number of flaring members' below the minimum stated, using flaring members the walls of which were straight from end to end in accordance with common prior practice, it was found that the velocities of the air streams in the passageways were too high and that there was insufficient diffusion and mixing of the air to render the device practical. Thus, there arose the problem of providing a device of the typementioned having fewer than the minimum number of flaring members stated and which yet would function with efficiency comparable to a device having the stated minimum, or more than the stated minimum, of flaring-members.

Accordingly, the general object of the present invention is to provide a device of the type mentioned embodying a construction to solve the problem mentioned; that is, to provide a device which has lesser than the stated minimum number of flaring members, whereby it is, more economical to produce than prior devices, and which, at the same time, is practically as effective as prior devices in eliminating any sensation of draft.

' With the foregoing general object in view, the invention consists in a device of the type mentioned embodying the novel combination and arrangement of features as will be hereinafter more fully described, illustrated in the accompanying drawing and defined in the appended claims.

In the accompanying drawing:

Figure 1 is a central, longitudinal section through a device constructed in accordance with one practical embodiment of the invention; and

Figure 2 is a fragmentary view lookin toward the inlet end of the device shown in Fig. 1.

Referring to the drawing in detail, it will be observed that the present device comprises a larger, outermost, open-ended, hollow, flaring member ID, a second, smaller, open-ended, hollow, flaring member ll spaced inwardly with respect I to said member I ii, a third, still smaller, open- 1y with respect to said second member I I, and an,

ended, hollow, flaring member I! spaced inwarde innermost fiaring member l3 spaced inwardly with respect to said third member I 2. Thus, said members cooperate to provide therebetween three successively smaller, successively inwardly disposed, flaring passageways designated as a,-b and 0, respectively.

From the smaller or rear, open end of the 1 member In a neck Id extends rearwardly for connection with an air supply duct, thereby to I provide for flow of supplied. air to the. device,

- smaller or rear, open end of the member II is while, in accordance with known practice. the

1 spectively, through the passageways a, b and c 1 at reduced velocities as compared with the duct or neck velocity of the supplied air, due to the flaring form of said passageways.

The innermost member i3 may-be hollow and livered from the device, but in being picked up and delivered'it obviously becomes intermixed tials between the supplied air and the room or enclosure air, little or no'sensation of draft due to the temperature difl" erential will be perceptible even at only short distances in advance of the device if provision is made for a sufficient amount of aspiratory action in the respective passageways.

Because the forward portions of the members I I and I2 have greater amounts of flare than the rear end portions i6 of said members, a much greater aspiratory action in the passageways b and c is obtained/than would be obtained if the rear and forward portions of said members H and I 2 had equal amounts of flare. Similarly, if the forward end portion of the member In should have a greater amount of flare than the rear end portion. l6 of said member, a much greater aspiratory action would be obtained in the passageway a than in case the forof conical'form as shown, or it may be of any other suitable flaring shape and may bev solid. If it is hollow, it may be either closed or open at its rear end as desired. Moreover, the mem- 1 bers III, II, l2 and I3 may be connected together i in assembled relationship in any preferred mandesired, the rear end portion l6 of the member ill, have lesser amounts of flare than the portions of said members forwardly of their said rear end portions. The rear end portion I8 of the mem-- ber lli determines the outer limit of the air 1 stream flowing through the passageway a and I the rear end portions ii of the members II and 1 I! determine the outer limits of the air streams flowing through the passageways b and c, respectively. Thus, within the forward end portions of the passageways b and c, the outer limits of the air streams flowing therethrough are spaced inwardly from the members II and, I2 defining l the outer portions of said passageways, as indicated by the light, dash and dot lines ll. Similarly, if the rear end portion I6 01' the member It has a lesser amount of flare than the forward portion of said member, the outer limit of the air stream flowing through the passagewaya will bespaced inwardly from the. forward end portion of said member l0.

Air flowing to the device through the neck I there is little difference in flare between the' forward and the rear end portions of the member III; a considerable difference in flare between the forward and the rear end portions of the member II, and also a considerable difference in flare between the forward and the rear end portions of the member l2, though not so great as between the forward and the rear end portions of the member II. This is because a considerably lesser amount of air flows through the passageway c than through the passageway b, due to"the considerably smaller area of the rear,

openend of the member l2 as-compared with the area of the mouth of the passageway 17.

, In other words; since more air flows through the 1 tends to preserve a direction of motiondirectly forwardly through the device; 1. e., a direction of motion axially with respect to the device. It

1 follows, therefore, that in being divided into separate streamsand in being deflected outwardly by the flaring members ll, [2 and I3, the air tends to hug the sides. of said members defining 1 the inner sides of the passageways a, b and c,

so that, naturally, high air pressures exist at the inner sides of said passageways and comparathe forwardly flowing air eventually is de caused to have substantially the same difl'usion and draft-sensation avoiding characteristics.

Because the air flowing from the passageway a v is directed mainly laterally outward, it is not necessary to have as great an aspiratory action in the passageway a as in the passageways b and 0. However, since, the outermost passageway a" of the present device has a more forward inclination than the corresponding passageway of a similar prior device having a greater number of iiaring members than the present device, and since, therefore, more air flows through the passageway a of the present device at a greater velocity than through the correspondingpassageway of a known device, it is'important to provide for obtaining a gr ter aspiratory action in the passageway 0. than in the corresponding pas- By providing a sageway of a similar prior device. This may be done by providing the forward end portion of the member III with a greater amount of flare than the rear end portion of said member. It

may further be accomplished by imparting a convex curvature or bulged form to the forward end portion of said member l0, thereby to ine crease the outer, low pressure area of the passageway a as compared with the low pressure area which would be provided if the wall of the forward portion of the member III were straight from end to end. In fact, it is desirable to impart a convex curvature or bulged form to the forward end portions of each of the members 10, II and II, as thereby, for any given diiference in flare between the forward and the rear end portions of said members, greater low pressure areas are obtained in the passageways a, b and 0. than would be obtained if the walls of the forward end portions of said members were longitudinally straight. Moreover, by convexly curving or bulging the forward end portions of the members HI,

I I and I2, the same results are obtained as would be obtained by increasing the flare of said portions if they were longitudinally straight. Ac-

cordingly, because of convexly curving or bulging,

the forward end portions of the members l0, l l and I2, desired amounts of aspiratory action may be obtained without excessively flaring said forward end portions.

Preferably, but not necessarily, the forward end portions of the members II and I! have their extreme forward ends extended laterally outward as indicated at IS. The outwardly directed extreme forward end portion of the member I I thus serves to direct air flowing from the passageway a away from the low pressure or aspiratory area of the passageway b, and the outwardly directed extreme forward end portion of the member l2 thus serves to direct air flowing from the passageway b away from the low pressure or aspirating area of the passageway c. In this way, interference of the streams'of air flowing from the passageways a and b with aspiration in the passageways b and 0, respectively, is practically avoided with the result that the aspirating effect in the passageways b and c is highly efficient.

From the foregoing it is believed to be manifest, assuming equal duct velocities of the supplied air,

that, although the air streams flowing through the passageways of the present device have higher velocities than the air streams flowing through the passageways of similar prior devices having greater numbers of flaring members than the present device, the present device is substantially as effective as prior devices in avoiding sensation, Y

of draft due to the much greater aspiratory action of the present device as compared with prior devices.

While the novel features of the invention have been illustrated and described in connection with a low-cost device having a lesser number of flaring members than have heretofore usually been provided in similar devices, it is apparent that v some or all of said features may advantageously be employed in prior or standard types of such devices having greater numbers of flaring members. It is also apparent that certain features of the invention may be used to the exclusion of other features thereof, either in a device as shown or in a similar device. Furthermore, regarding the lengths of the forwardand rear, differently flared portions of the flaring members, it is pointed out that these may be varied within wide limits, although it is preferred to have the rear end portions l6, [6 only of sufllcient lengths to properly control the outer limits of the air streams and to have the forward end portions as long as practicable to afford low pressure areas of maximum length and area.

Without further description it is thought that the features and advantages of the invention will be readily apparent to those skilled in the art, and it will, of course, be understood that changes in the form, proportion and minor details of construction may be resorted to, without departing from the spirit 'of the invention and scope of the appended claims.

I claim:

1. An air distributing device comprising a plurality of successively smaller, open-ended, hollow, flaring members spaced successively inwardly of one another to provide a plurality of flaring air passageways therebetween, the rear end portion of at least one of said members being straight in cross section and having an amount of flare such that a forward prolongation thereof extends outwardly of the outermost portion of the next adjacent inwardly disposed member by an amount to permit the major portion of air supplied through the passageway between said members to flow in a straight path through sa d passageway, said flrst mentioned member, forwardly of its straight-walled rear end portion, being of internal concave, external convex form in cross section and being disposed outwardly of a forward prolongation of the said straight-walled rear end portion thereof to provide in the outer side portion of the passageway between said members a large area for air aspiration.

2. An air distributing device as set forth in claim 1 in which the forward end portion of the first mentioned member is directed outwardly relative to the concavo-convex portion of said member.

3. An air distributing device comprising a plurality of successively smaller, open-ended, hollow flaring members spaced successively inwardly of one another to provide a plurality of flaring passageways therebetween, the forward end portion of at least.one of said members being curved outwardly, the rear end portion of said member being straight in cross section'and having an amount of flare such that a forward prolongation thereof extends outwardly of the outermost portion of the next adjacent inwardly disposed -member by an amount'to permit the major portion of air supplied through the passageway be-' tween said members to flow in a straight path through said passageway, the portion of said flrst mentioned member between its straight-walled rear end portion and its front end outwardly 'curved portion being of internal concave, external convex'form in cross section and being disposed outwardly of a forward prolongation of the straight-walled rear end portion of said member.

being .straight in cross section and each having an amount of flare such that a forward prolongation thereof extends outwardly of the outermost portion of the next adjacent inwardly disposed member by an amount to permit the major portion of air supplied through the passageways inwardly of said members, respectively. to flow in straight paths through said passageways, each of said 'two members, forwardly of its-straightwalled rear end portion, being of internal concave, external convex form in cross section and being disposed outwardly of'a forward prolongation of its straight-walled rear end portion, the amount; of outward disposition of the concavoconvex forward portion of the outerof said two -members with respect to a forward prolongation of its straight-walled rear end portion being rality of successively smaller, open-ended-hollow,

flaring members spaced successively inwardly of one another to provide a plurality of flaring passageways therebetween, at least one of said members being of internal concave, external convex form in cross section throughout a major portion of its length and being spaced outwardly from the next adjacent inwardly disposed member by an amount to permit the major portion of air supplied through the passageway between said members to flow therethrough in a straight path, thus to insure a large area for air aspiration in the outer side portion of said passageway.

6. An air distributing device as set forth in claim 5 in which the forwardvend portion of the flaring member particularly defined is directed outwardly relative to the concavo-convex portion of said member.

FRANZ J. KURTH. 

